1. Field of the Invention
The present invention relates to a device testing apparatus for testing IC chips and other electronic devices at a predetermined temperature, more particularly relates to a device testing apparatus which accurately controls the temperature of the electronic devices even if the electronic devices generate heat on their own during the testing and thereby enables the electronic devices to be tested at the desired test temperature.
2. Description of the Related Art
In the process of production of a semiconductor device etc., a tester is necessary for testing the finally produced IC chip or other device. As one type of such a tester, there is known an apparatus for testing an IC chip at high temperature, ordinary temperature or temperature conditions lower than ordinary temperature. This is because it is guaranteed as one of the features of an IC chip that it operate well as high temperature, ordinary temperature, or low temperature.
In such a tester, the top of the test head is covered by a chamber, the inside is made an air-tight space, an IC chip is coveyed on to the test head, the IC chip is pushed against the test head for connection, and the IC chip is tested while maintaining the inside of the chamber at a certain temperature range. This type of test is used to test IC chips well and sort them into at least good chips and defective chips.
Along with the increasingly higher speeds and increasingly higher integration densities of IC chips in recent years, the heat generated by the chips themselves at the time of operation becomes larger. Such heat is generated at the time of testing IC chips as well. Even if the inside of the chamber is maintained at a constant temperature, it is therefore be difficult to test IC chips at the intended test temperature. For example, as much of 30 watts of heat is sometimes generated depending on the type of the IC chip. In this way, when testing IC chips generating large heat, no matter how much effort is made to hold the inside of the chamber at a constant temperature, it becomes difficult to test the IC chips in a prescribed range of test temperature. When unable to test IC chips at the prescribed test temperature, there is the problem that the reliability of the tests ends up falling.
Recently, therefore, effort has been made to develop testing apparatuses with temperature sensors attached to the suction heads for picking up and holding the IC chips and pressing and holding them against the sockets of the test heads, measuring the temperature of the IC chips at the time of the tests, and blowing cooling air when the IC chips rise to more than a set temperature due to the heat they generate.
Some types of testing apparatuses, however, have the suction heads attached to rotary arms which rotate along an infinite path. In testers where the suction heads move in this manner, there is the problem that when attaching temperature sensors to the suction heads, the electrical wiring from the temperature sensors becomes complicated. If the electrical wiring from the temperature sensors is formed by ordinary electrical wiring, the electrical wiring will become twisted along with the rotation of the rotary arm, so it is necessary to use rotary joints or other special connectors in the middle of the electrical wiring. Accordingly, the testing apparatus become higher in price and the problem occurs of rotational wear at the rotary joints of the electrical wiring and of a decline in the durability.
Further, in the worst case, the cables of the temperature sensors are liable to break due to movement of the suction heads. Further, in a structure using suction passages of the suction heads to blow cooling air to the IC chips, it is not possible to blow a sufficient amount of cooling air to the IC chips and therefore not possible to deal with cases of a large amount of heat generated.